Healthier, stronger trees, thanks to world-class care

Amresh Gunasingham, Strait Times 14 Mar 09;

THE garden city is home to 1.3 million trees, which are often lashed by monsoon rains and lightning strikes. But Singapore is winning the fight against falling trees and broken branches.

World-class training, state-of-the-art technology and improved pruning techniques have reduced the number of falling trees or broken branches to 1,000 cases annually, said the National Parks Board (NParks), which looks after trees along most roads and in parks and nature reserves.

This is down two-thirds from the 3,000 cases recorded nine years ago.

The reduction is a 'major achievement in minimising safety risks and inconvenience to the public', said an NParks spokesman.

The director of streetscape at NParks, Mr Simon Longman, said the improvement was in part due to better training and a certification programme for arborists, or tree specialists, who select the most suitable trees for planting, and ensure they are in top condition.

To date, 220 certified arborists are on the books of the Centre for Urban Greenery and Ecology (CUGE), a training centre set up in Singapore two years ago to cater to the national landscaping workforce.

NParks also utilises advanced equipment which uses sound waves and resistance measures to detect the internal conditions of trees - such as cracks, cavity or decay - which make them more vulnerable to failure.

Dr Tan Puay Yok, assistant director of CUGE, said that monsoon weather conditions, which bring heavy rain and thunderstorms, makes trees in Singapore more vulnerable to being uprooted.

On average, Singapore has 270 days each year when lightning strikes.

To help protect trees from lightning, NParks is using an improved pruning technique targeted at minimising the weight imposed by a tree's crown on its roots so that it is less likely to topple.

More techniques are being tested.

A $130,000 project, funded by NParks and Nanyang Technological University, is experimenting with a special soil mix to grow rain trees, a common species found along roadsides here, in spaces where they could not take root before, such as footpaths.

Structural soil, which is a mixture of coarse gravel and varied concentrations of topsoil, can enhance tree stability as it allows for deeper root penetration and access to water and nutrients required for growth.